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1 #include<lemon/lp_glpk.h> |
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2 #include<lemon/graph_reader.h> |
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3 #include<lemon/list_graph.h> |
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4 |
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5 using namespace lemon; |
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6 |
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7 template<class G,class C> |
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8 double maxFlow(const G &g,const C &cap,typename G::Node s,typename G::Node t) |
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9 { |
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10 LpGlpk lp; |
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11 |
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12 typedef G Graph; |
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13 typedef typename G::Node Node; |
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14 typedef typename G::NodeIt NodeIt; |
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15 typedef typename G::Edge Edge; |
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16 typedef typename G::EdgeIt EdgeIt; |
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17 typedef typename G::OutEdgeIt OutEdgeIt; |
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18 typedef typename G::InEdgeIt InEdgeIt; |
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19 |
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20 typename G::template EdgeMap<LpGlpk::Col> x(g); |
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21 lp.addColSet(x); |
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22 |
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23 for(EdgeIt e(g);e!=INVALID;++e) { |
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24 lp.colUpperBound(x[e],cap[e]); |
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25 lp.colLowerBound(x[e],0); |
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26 } |
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27 |
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28 for(NodeIt n(g);n!=INVALID;++n) if(n!=s&&n!=t) { |
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29 LpGlpk::Expr ex; |
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30 for(InEdgeIt e(g,n);e!=INVALID;++e) ex+=x[e]; |
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31 for(OutEdgeIt e(g,n);e!=INVALID;++e) ex-=x[e]; |
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32 lp.addRow(ex==0); |
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33 } |
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34 { |
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35 LpGlpk::Expr ex; |
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36 for(InEdgeIt e(g,t);e!=INVALID;++e) ex+=x[e]; |
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37 for(OutEdgeIt e(g,t);e!=INVALID;++e) ex-=x[e]; |
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38 lp.setObj(ex); |
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39 } |
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40 |
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41 lp.solve(); |
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42 |
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43 return 0; |
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44 } |
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45 |
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46 int main() |
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47 { |
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48 LpGlpk lp_glpk; |
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49 |
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50 ListGraph g; |
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51 ListGraph::Node s=g.addNode(); |
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52 ListGraph::Node t=g.addNode(); |
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53 |
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54 ListGraph::EdgeMap<double> cap(g); |
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55 |
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56 GraphReader<ListGraph> reader(std::cin,g); |
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57 reader.addEdgeMap("capacity",cap).run(); |
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58 |
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59 maxFlow(g,cap,s,t); |
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60 |
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61 } |